Patent GB-724031-A (GB)
Title: Improvements relating to the remote guidance of flying objects
IPC: F41G7/24
Filed: 1952-08-29
Abstract: 724,031. Radio-navigation. CONTRAVES AKT.-GES., and PATELHOLD PATENTVERWERTUNGS- & ELEKTRO-HOLDING AKT.-GES. Aug. 29, 1952 [Aug. 30, 1951], No. 21838/52. Class 40 (7). The invention relates to a system for the remote guidance of a flying object O Fig. 1, along a path SM defined by an ultra - high - frequency beam R executing a conical scan and in which the actual co-ordinates r, # # of the object with reference to the desired position O<SP>1</SP> are determined at the object by measuring the amplitude and phase respectively of the modulation imparted to the received signals by the scanning motion of the beam. In accordance with the invention, a reference signal of fixed phase is made available at the object, to enable ##  to be determined, by keying the ultrahigh-frequency beam with pulses at a repetition frequency which is varied in accordance with the instantaneous angular position of the beam. At the object the received pulses are demodulated and limited to obtain a signal at the repetition frequency and this signal is then applied to a frequency discriminator to derive the reference signal of fixed phase. At the transmitter S, Fig. 2, the antenna D is caused to execute a conical scan under the control of a device A at a frequency #o determined by an oscillator Q. A reference signal U2 is obtained from the same oscillator and applied to modulate the frequency of an auxiliary signal U3 of substantially higher frequency in a device Z. The resulting signal U4 is then transformed to a pulse signal U5 in a limiter and differentiator circuit J and applied to key the transmitter S whereby pulses of energy are radiated. The signal received at the flying object appears as shown in Fig. 6a and comprises pulses varying in frequency over a time cycle #<SP>1</SP> determined by the conical scan period and varying in amplitude at the conical scan frequency in dependence on the degree of displacement from the desired path. The phase of the frequency modulation is fixed as determined by the reference signal U2 at the transmitter whereas the phase of the amplitude modulation is variable as determined by the angular displacement # #. The amplitude of the modulation is determined by the lateral displacement r. In the receiver, Fig. 5, the signal is demodulated at G to derive the pulse signal U12, Fig. 6b, and this is applied to a band-pass amplifier ZF to obtain the fundamental component U13, Fig. 6c, corresponding to the auxiliary signal U3 impressed at the transmitter. The signal is then passed to an amplitude limiter Be and frequency discriminator Di at the output of which appears a signal U17, Fig. 6e; corresponding to the reference signal U2. The pulse train U13 is also detected by a rectifier SG to derive the modulation component U18, Fig. 6f. The two signals U17 and U18 are then applied to a control device ST which derives the quantities r, # # corresponding respectively to the angular, and lateral displacements and operates automatically to restore the object to follow the desired path. Automatic gain control of the received signal is obtained by a rectifier AR which derives a voltage U from the signal U13 and controls amplifier ZF.